నైరూప్య

Effects of annealing and annealing cooling media in corrosion resistance and microhardness of low content chromium nickel steel

Hossam Ibrahim Al-Itawi, Firas Al-Quran

To study the effect of intermediate spheroidal annealing on some properties of ametal, samples of chromium-nickel stealwere chosen. The sampleswere carburized, normalized, annealed, hardened and tempered. The microhardness and corrosion resistance in acidicmedia were measured. The effect of annealing cooling media was also studied. Cooling media was chosen in a way to characterize the effect of cooling rate on steal properties: furnace cooling media; slow cooling rate, air cooling media; fast cooling rate, and oil cooling media; fast cooling rate. This paper showed that intermediate spheroidal annealing affect in alloys properties. It was found that, the hardness of the material increases and decreases in dependence on annealing temperature and holding time, but the results werenÂ’t predictable; each temperature and cooling rate has its pattern. The study shows an increase in the corrosion resistance of the material due mainly to spheroidal annealing process. In general the best result showed samples annealed at 740 ï‚°C, 60 min. for microhardness, and 740 ï‚°C, 45 min for corrosion resistance, especially for oil cooling media.